1. Field of the Invention
The present invention relates to a video recording apparatus, a video recording method, a video transmission method, a program for the video recording method, and a storage medium having stored the program for the video recording method. For example, the present invention can be applied to a video camera that employs a hard disk drive for its recording medium. In the present invention, while compressed video and audio data are multiplexed together using fixed-data-length packs according to an optical disk format, specific information that includes information necessary for generating a navigation pack and is difficult to obtain without analyzing the video and audio data packs is added to streaming data such that the specific information is assigned to each GOP in the streaming data. This considerably shortens the time necessary for recording onto an optical disk, such as a DVD, as compared with in related art.
2. Description of the Related Art
In recent years, there has been provided a portable video camera, which is a video recording apparatus, employing a hard disk drive, a magnetic tape, or the like for its recording medium and records a video captured thereby on the recording medium. Such a video recording apparatus records streaming data containing video data and audio data on the recording medium using the MPEG (Moving Picture Experts Group)-2 technology. In this process, the video and audio data are compressed while a sequence of GOPs (Group Of Pictures) are set, and the resultant encoded data is subjected to time division multiplexing to generate the streaming data.
In contrast, a DVD (Digital Versatile Disk) recorder, which is a similar video recording apparatus, compresses the video and audio data using the MPEG-2 technology as does the above-described portable video camera, and records the resultant data on a DVD which is an optical disk according to a specified format.
As illustrated in FIG. 12A, the DVD recorder records the video and audio data while dividing information recording surface of the DVD into a lead-in area (innermost), a file system area, a management information area, a data recording area, and a lead-out area.
The file system area and the management information area are recording areas for storing management information used for managing video data files recorded on the DVD, and are provided with UDF (Universal Disk Format) and VMG (Video Manager), respectively.
The UDF is an area corresponding to a file management system of a computer that complies with ISO 9660 and UDF specifications, and stores management information used for managing the data recording area using a format designed to achieve compatibility with the file system of the computer.
In contrast, as illustrated in FIG. 12C, the VMG is an area for management information for a DVD player/recorder, and management information for the VMG is stored in VMGI (VMG Information), which is located at the top of the VMG. VMGM VOBS (Video OBject Set for VMG Menu), which follows the VMGI, stores actual data of the VMG. VMGI BUP (VMGI for Back UP), which follows the VMGM VOBS, stores a backup copy of the VMGI.
The data recording area is a recording area used for storing actual data of the DVD, and stores the encoded video and audio data obtained from the MPEG-2 data compression with a video title set (VTS) as a basic unit. As illustrated in FIG. 12D, each video title set (VTS) is composed of VTSI (Video Title Set Information), VTSM VOBS (Video Object Set for the VTSM), VTSTT VOBS (Video Object Set for Titles in a VTS), and VTSI BUP (Backup of VTSI), which are arranged in this order.
The VTSTT VOBS stores the encoded video and audio data. The VTSI stores storage position information which is management information used for managing the actual data stored in the VTSTT VOBS, and the like. The VTSM VOBS stores a title menu of the video data. Note that the VTSM VOBS is optional. The VTSI BUP is a backup copy of the VTSI.
In this type of optical disks, when access is made from the computer, the UDF is used to search for and reproduce a desired file, whereas when access is made from the DVD player/recorder, the VMG is used to search for and reproduce a desired file.
FIGS. 13A to 13F are diagrams illustrating the details of the VTSTT VOBS. Hereinafter, the VTSTT VOBS will be referred to as “VOBS” for short when appropriate. Incidentally, the VMGM VOBS and the VTSM VOBS store their respective actual data according to the same format as shown in FIGS. 13A to 13F.
The VTSTT VOBS is a collection of one or more video objects (VOBS). Each VOB is assigned a VOB ID, which is an identification code, and is composed of one or more cells (Cells). Each cell is assigned a cell ID, which is an identification code, and is provided with one or more video object units (VOBUs).
Each VOBU is constructed of one GOP assigned thereto, and is constructed of a sequence of packs with a navigation pack (NV PCK) located at the top. Each of the packs has a fixed data length of 2048 bytes. Each VOBU has the navigation pack arranged at the top and is also provided with a video pack (V PCK) that stores the encoded video data, an audio pack (A PCK) that stores the encoded audio data, a subpicture pack (SP PCK) that stores subpicture data, etc.
The navigation pack (NV PCK) has assigned thereto control information necessary for reproducing the video and audio data contained in each cell. Specifically, the NV PCK has assigned thereto information of the video and audio data contained in the GOP within the VOBU to which the NV PCK belongs, information indicating relationships with other VOBUs that are reproduced in combination, and so on.
As such, the navigation pack (NV PCK) is composed of a pack header, presentation control information (PCI), and data search information (DSI), which are arranged in this order. The presentation control information (PCI) has assigned thereto control information concerning reproduction display, such as angle information used for non-seamless reproduction and information used for highlight display of a subpicture. The data search information (DSI) has assigned thereto control information concerning access.
As illustrated in FIGS. 14A and 14B, the data search information (DSI) is constructed of DSI GI, SML PBI, SML AGLI, VOBU SRI, and SYNCI, and subsequent to the SYNCI, a reserved area is provided.
The DSI GI stores, as general information, a logical block number of the corresponding navigation pack and position information concerning the DSI, such as an ending address of the VOBU. The SML PBI stores information necessary for realizing seamless reproduction, such as a category of seamless VOBU, reproduction start and end times of video within the VOB, and a reproduction end time of audio within the VOBU. The SML AGLI stores angle information used for seamless reproduction, which is information concerning a destination address at the time of angle change. In this SML AGLI, effective information is set when necessary.
The VOBU SRI stores a starting address of a VOBU that belong to the same cell and is reproduced within 0.5×n seconds before or after the reproduction start time of the VOBU that contains the DSI to which the VOBU SRI belongs. Use of the information stored in the VOBU SRI enables VOBU-based search.
The SYNCI stores synchronization information, i.e., address information of the audio and subpicture data that are reproduced in synchronization with the video data within the VOBU that contains the DSI to which the SYNCI belongs.
As described above, the video recording apparatus that adopts the DVD format compresses the video data and the audio data using the MPEG-2 technology and subjects the navigation packs (NV PCKs) and the resulting encoded video and audio data to time division multiplexing to generate the streaming data. Then, the video recording apparatus records the streaming data on the DVD.
Regarding data recording onto the DVD, Japanese Patent Laid-open No. 2004-312663 and Japanese Patent Laid-open No. 2005-79823 have proposed techniques of assigning to the VOBU an additional information pack containing additional information in order to enhance the degree of convenience.
Some users sometimes upload a video captured and recorded by the portable video camera or the like to the computer, edit the video using an editing software program, and records the edited video on the DVD. In this case, from the fact that the portable video camera or the like also compresses the video and audio data using the MPEG-2 technology and records the compressed video and audio data, it might appear that the recording of the edited video on the DVD can be achieved by a simple process.
The fact is, however, that when recording the edited video on the DVD, it is necessary to analyze the compressed video and audio data to obtain data necessary for generation of the navigation pack (NV PCK), and that, unfavorably, this process takes much time.